Turkey's NATO allies on Wednesday called for a rapid de-escalation in tensions between Ankara and Moscow after Turkish fighter jets shot down a Russian war plane on the Syrian border, sparking fears of a wider conflict.
Moscow said one of the pilots was killed by fire from the ground after parachuting out of the burning plane on Tuesday, while the second had been taken to safety by the Syrian army.
The defence ministry said a Russian soldier was also killed when a helicopter search-and-rescue operation came under fire although others were evacuated.
With the incident risking serious harm for Ankara-Moscow relations, Turkey said the Russian plane had violated its air space 10 times within a five minute period, but Russia insisted it had never strayed from Syrian territory.
President Vladimir Putin reacted furiously to what he described as a "stab in the back committed by accomplices of terrorists", and insisted the plane had posed no threat.
The shooting also risks derailing efforts to bring peace to Syria that were gaining tentative momentum following the November 13 Paris attacks claimed by Islamic State militants who control swathes of northern Syria.
US President Barack Obama said Washington's NATO ally Turkey had a right to defend its airspace but said his priority was to make sure the standoff did not escalate.
"I think it is very important for us to right now make sure that both the Russians and the Turks are talking to each other and find out exactly what happened, and take measures to discourage any kind of escalation," Obama told reporters.
"Hopefully, this is a moment in which all parties can step back and make a determination as to how their interests are best served," Turkish President Recep Tayyip Erdogan and Obama agreed on the need to reduce tensions and prevent a repeat of similar incidents in a phone call late on Tuesday, the Turkish presidency said.
In his first reaction to the incident, Erdogan said: "Everyone must respect the right of Turkey to protect its borders." Following an extraordinary meeting of the alliance called by Ankara, NATO chief Jens Stoltenberg urged both sides to try to calm the crisis between the two rival players in the Syrian conflict.
"Diplomacy and de-escalation are important to resolve this situation," he said.
The Turkish ambassador to the United Nations Halit Cevik said in a letter to the Security Council that two planes were involved, one of which was shot down while the other left Turkish air space.
He said both planes had flown 2.19 kilometres into Turkish airspace for 17 seconds from 0724 GMT on Tuesday.
Ankara and Moscow are already on starkly opposing sides in the over four year Syrian civil war, with Turkey wanting to see the ousting of President Bashar al-Assad but Russia one of his last remaining allies.
There had been fears of such a mid-air incident since Russia launched air strikes in Syria in September, to the consternation of nations already involved in a US-led anti-IS coalition.
Turkey had bitterly condemned Russia's campaign, saying it was aimed at hitting Syrian rebels and buttressing the Assad regime rather than hurting IS jihadists.
In the days leading up to Tuesday's incident, Ankara had also accused Russia of bombing villages in northern Syria populated by Turkmen, a Turkic speaking minority with close ties to Turkey.
Two Russian pilots were seen on images parachuting to the ground after the shooting down but their uncertain fate risks creating further tensions.
Russian military spokesman General Sergei Rudskoi said one had been killed by fire from the ground. Russia's ambassador to France, Alexander Orlov, told French radio the second pilot was "picked up" by the Syrian regime army and was now safe.
Rudskoi said a soldier had been killed in a failed bid to rescue the pair after one of his squadron's helicopters was damaged by gunfire and had to land. The other members of the squad were successfully evacuated.
Rudskoi warned the shooting down would have the "the gravest consequences" and said Russia's Moskva guided missile cruiser would be stationed near the Syrian Mediterranean port of Latakia.
As well as cancelling a visit to Turkey planned for Wednesday, Russia Foreign Minister Sergei Lavrov warned Russians against travel to the country, which would be a huge blow for the Turkish tourism industry.
Turkey's pro-government press applauded the shooting down, with Ilnur Cevik in Daily Sabah saying the Russian incursion was "the last drop for Turkey to break its silence towards Russia's violence in the region".
However columnist Mehmet Yilmaz in the mainstream Hurriyet daily accused Erdogan of plunging Turkey into a "quagmire", warning of "grave political and economic consequences for Turkey".
The repercussions of the incident also affected global markets with oil prices turning higher and stocks down with shares in airlines and travel firms particularly hit.